Adjustable back chair and locking mechanism



United States Patent [72] Inventors Joseph J. Hibl Boulder; 1 Paul E. Ferguson, Arvada, Colo.; Vernon M. Eckels, Wichita, Kans. [21] Appl. No. 814,069 [22] Filed Apr. 7, 1969 [45] Patented Dec. 29, 1970 [73] Assignee Beech Aircraft Corporation Wichita, Kans. a corporation of Delaware [54] ADJUSTABLE BACK CHAIR AND LOCKING MECHANISM 11 Claims, 5 Drawing Figs.

[52] [1.5. CI 297/374v [51 Int. Cl A47c 1/027 [50] Field of Search 297/374 [56] References Cited UNITED STATES PATENTS 365,266 6/1887 Maddox 297/375 1,701,604 2/1929 Boery..... 297/374 1,751,599 3/1930 Prassas... 297/374 3,257,146 6/1966 Mahoney 297/388 Primary Examiner- Reinaldo P. Mac'hado Attorney-Miller & Brown ABSTRACT: The invention comprises an adjustable aircraft seat which utilizes a spring tensioned web belt to position the pivotally mounted backrest in any desired inclination. The belt is releasably held by a slidable locking bar forced against a guide roller by the tension in the belt and released by a manual lever which pries the locking bar away from the guide roller allowing the backrest to be repositioned.

PATENTED M829 19m SHEET 1 OF 2 INVENTORS JOSEPH J. HIBL PAUL E. FERGUSON BY VERNON M. ECKELS ATT ORINEY PATENTED [15029 I970 SHEET 2 OF 2 F/GZ' Iii- IMVENTOILS JOSEPH J. HIBL PAUL E. FERGUSON VERNON M. ECKELS ATTORNEY BACK CHAIR AND LOCKING MECHANISM BACKGROUND OF THE INVENTION ADJUSTABLE held by a slidable locking bar which grips the belt between a stationary member due to the tension placed on the belt.

Most conventional aircraft seats utilize a complex latching construction for positioning the backrest with a limited number of positions. The present invention provides a simplified high strength structure which can reposition the backrest in an infinite number of positions with a very slight unlocking force. The greater the inertia load on the backrest the stronger grip the locking bar exerts on the belt. While the locking mechanism can withstand loads of several thousand pounds, it can be readily opened or released with a minimum of effort.

It is therefore the principal object of the present invention to provide a novel and improved adjustable chair structure utilizing a web belt and locking mechanism to position a tilting backrest. 1

Another object of the present invention is to provide a simplified high strength locking mechanism which withstands heavy loads and can be readily released with a minimum of force.

A further object of the present invention is to provide an improved locking belt mechanism which grips the belt in locking relation due to the constant tension in the belt except when overridden by the release lever.

Further objects and advantages of the invention will become apparent from the following description as read in connection with the accompanying drawings in which:

FIG. 1 is a side elevational view of the chair with portions of the legs broken away to shown the belt and locking mechanism and portions of the seat and backrest removed to conserve space;

FIG. 2 is a fragmentary view to an enlarged scale of the locking mechanism gripping the belt in the locked position;

FIG. 3 is a similar view to FIG. 2 with the locking mechanism in the release position;

FIG. 4 is a fragmentary sectional view taken along line of FIG. 3; and

FIG. 5 is a perspective view of the locking bar.

Referring now to the drawings for a detailed description and, more specifically, to FIG. I there is shown an aircraft chair generally identified by reference numeral 10. Chair comprises a pair of base members 12 supporting a seat frame 13 and a backrest 14. Portions of the seat frame and backrest are broken away since they have no pertinence to the invention. The base member 12 is U-shaped,'defining a pair of legs 15 and 16. The member 12 has a hollow box-shaped cross section made up of sidewalls 17 and 18 and end walls 19 and 20. An identical member 12, not seen in the drawings, is located immediately behind the base member 12. Both base members 12 are connected to the seat member 13 forming a rigid fourlegged structure. Extending outwardly from the sidewall 18 is a mounting lug 2I for supporting the backrest 14. Adjacent the lug 21 is an opening 22 in the end wall 19 for receiving the extending portion 23 of the backrest. The backrest is pivotally mounted to the lug 21 through pin 24. Connected to the extending portion 23 through pin 30 is a web belt 25 for positiming and retaining the backrest in various positions of inclination. The belt 25, is positioned inside the base member 12 and passes over a roller 27 reversing its direction. The belt 25 then passes around a locking bar 28, between stationary guide rollers 29 and 31. The end of the belt is attached to a tension spring 32 which in turn is anchored to the base member 12 through pin 23. The action of spring 32 maintains a constant tension on the belt regardless of the position of the backrest l4. t The locking bar 28 is shaped with diametral lugs 35 located at each end, as best seen in FIG. 5. The lugs 35 are slidably received in a pair of opposing slots 36 located in respective sidewalls 17 and I8 of the base member. The slots are positioned so that any tension on the belt, from either end, forces the locking bar towards the guide roller 29 into gripping relation with the belt. The surface of the locking bar 28 can be roughened or knurled to increase the sliding friction of the belt over the bar, if desired. Pivotally mounted on a pin 38 is a release lever 39 having a relatively short work-engaging arm 40 which engages lug 35. A second work engaging arm 41, which engages the opposing lug 35 is also anchored to pin 38, as seen in FIG. 4. The hand-engaging arm 42 of the release lever has a substantial mechanical advantage over arm 40 and extends outwardly towards the front edge of the seat frame 13.

OPERATION FIG. 2 of the drawings illustrates the locking mechanism in its locked position with the web belt 25 held between the guide roller 29 and nonrotating locking bar 28. The constant tension in the belt caused by the spring 32 maintains the locking bar 28 in the locked position. When a force is directed against the backrest 14, an additional tension is put on that portion of the belt 25 passing over the bar 28 from the right, as viewed in the drawings. The effect of the additional tension forces the locking bar 28 into tighter engagement with the belt.

When it is desired to reposition the backrest 14, the arm 42 of the release lever is depressed to the FIG. 3 position. This rotation of arm 40 forces locking bar 28 away from roller 29, allowing belt 25 to freely slide therebetween. If there is no load on the backrest, tension from spring 32 has an adequate force to move the backrest into an erect or upright position when the belt is released.

Normally a person would be sitting in the chair when the backrest is repositionedfWhen the user depresses the lever 39 to the FIG. 3 release position, he can lean back against the backrest overcoming the spring 32 and tilt it to any desired position. By releasing the lever the backrest will be retained in that position since the tension of spring 32 will force the locking bar 28 back into the FIG. 2 locked position. The release lever 39 is horizontally positioned so as to minimize any inertia effort caused by impact of the aircraft, that would tend to release the belt.

Having described the invention with sufficient clarity to enable those familiar with the art to construct and use it.

We claim: I

1. A belt locking assembly for retaining an object in a stationary position including:

a base member 12 having at least one guide roller 29 mounted therein;

a locking bar (28) with supporting lugs 35 at each end thereof positioned in juxtaposed relation to the guide roller, the lugs being slidably received in a pair of slots 36 in the base member extending toward the guide roller;

a belt means 25 passing substantially around the locking bar and between the guide roller and locking bar, having one end attached to the object;

spring means 32 anchoring the opposite end of the belt means to the base member whereby a constant tension is maintained on the belt urging the locking bar towards the guide roller in gripping relation with the belt means; and

a lever means 39 pivotally mounted on the base member with one end positioned in contacting relation with the lugs on the locking bar and upon rotation of the lever means, forces the locking bar away fromthe guide roller releasing the belt.

2. A locking belt assembly as set forth in claim 1, wherein the end of the belt means attached to the object lies in a plane substantially parallel with the slots in the base member whereby any tension in the belt means caused by the object urges the locking bar into a tighter gripping relation with the belt means.

3. A locking belt assembly as set forth in claim 1, wherein the belt means approximate the locking bar lies in planes substantially parallel with the slots in the base member so that any tension from either end of the belt means urges the locking bar into tighter gripping relation with the belt means.

4. A locking belt assembly as set forth in claim 1, wherein the end of the belt means attached to the object lies in a plane substantially parallel with the slots in the base member whereby any tension in the belt means caused by the object,

urges the locking bar into a tighter gripping relation with the belt means, the lever means including a first arm 40 extending from the pivotal mount into contacting relation with the lugs on the locking bar between the locking bar and guide rollers and a second arm 42 for manual positioning, having a length at least three times that of the first arm.

5. A locking belt assembly as set forth in claim 1, wherein the belt means approximate the locking bar lies in planes substantially parallel with the slots in the base member so that any tension from either end of the belt means urges the locking bar into tighter gripping relation with the belt means, the lever means including a first arm 40 extending from the pivotal mount into contacting relation with the lugs on the locking bar between the locking bar and guide roller and a second arm 42 for manual positioning, extending in the direction of movement of the overall belt locking assembly and object, having a length at least five times that of the first arm whereby a substantial mechanical advantage is achieved when forcing the locking bar out of its gripping position.

6. An adjustable back chair comprising:

a base member 12 supporting a seat portion 13;

a guide roller 29 attached to the base member;

a backrest l4 pivotally mounted to the base member;

a locking bar 28 supported at its ends in a pair of slots 36 in the base member, the slots extending substantially toward the guide rollers allowing the pin to slide into juxtaposed belt-locking relation with the guide roller;

a belt means 25 passing around the locking bar and between said guide roller and locking bar having one end attached to the backrest;

spring means 32 anchoring the opposite end of the belt means to the base member whereby the tension in the belt urges the locking bar into belt-locking relation with said guide rollers; and

lever means 39 pivotally mounted on the base member for urging the locking bar away from the guide rollers to release the belt and reposition the backrest.

7. An adjustable chair as set forth in claim 6, including a second guide roller 27 supporting the belt means between the locking bar and backrest; the said guide rollers being so positioned on the base members that the tension in the belt from the backrest urges the locking pin into engagement with a first guide roller.

8. An adjustable chair as set forth in claim 2, wherein the locking bar has a pair of diametral lugs 35 at its ends which are slidably carried in the slots in the base member preventing the locking pin from rotating.

9. An adjustable chair as set forth in claim 6, including a second guide roller 27 supporting the belt means between the locking bar and the backrest, in a plane substantially parallel with the slots in the base member whereby the tension in the belt means caused by the backrest urges the locking bar into tighter gripping relation with the belt means.

10. An adjustable chair as set forth in claim 6, wherein the locking bar has a pair of diametral lugs 35 at its ends which are slidably carried in the slots in the base member preventing the locking pin from rotating, the lever means including a first arm 40 extending from the pivotal mount into contacting relation with the lugs on the locking bar between the locking bar and guide rollers and a second arm 42 for manual positioning, havinga length at least three times that of the first arm.

1. An ad ustable chair as set forth in claim 6, including a second guide roller 27 supporting the belt means between the locking bar and the backrest, in a plane substantially parallel with the slots in the base member whereby the tension in the belt means caused by the backrest urges the'locking bar into tighter gripping relation with the belt means, the lever means including a first arm 40 extending from the pivotal mount into contacting relation with the lugs on the locking bar between the locking bar and guide roller and a second arm 42 for manual positioning, extending in the direction of movement of the overall belt locking assembly and object, having a length at least five times that of the first arm whereby a substantial mechanical advantage is achieved when forcing the locking bar out of its gripping position. 

